Long Term Evolution (LTE) belongs to the fourth generation (4G) of wireless cellular communication technologies. As a multicarrier system, an LTE system adopts the orthogonal frequency division multiplexing (OFDM) technology, in which physical resources of the LTE system are composed of subcarriers in a frequency domain and symbols (about 71 us) in a time domain. Each symbol may include a plurality of subcarriers, and a plurality of symbols constitute one subframe. The adoption of a cyclic prefix (CP) enables a CP-OFDM system to eliminate multipath delay and to divide a frequency selective channel into a set of parallel flat channels, which successfully simplifies a channel estimation method and achieves a high accuracy in the channel estimation. However, the performance of the CP-OFDM system are more sensitive to frequency offset and time offset of adjacent sub-bands, which is mainly because spectrum leakage of this system is large, and thus it is prone to cause sub-band interference. At present, the LTE system uses a guard interval in the frequency domain, which reduces a spectrum efficiency. Therefore, new technologies are needed to inhibit out-of-band leakage.
In the industry, a study on the fifth generation (5G) of wireless communication technologies has been started, and inhibition of out-of-band leakage is an important direction of study on the 5G technologies. In new-type multicarrier schemes mentioned in some related articles, filter bank multicarrier (FBMC) and generalized frequency division multiplexing (GFDM) technologies can inhibit out-of-band leakage. However, these technologies are not satisfactory in compatibility with CP-OFDM technology of the LTE, channel estimation, combination with multiple input multiple output (MIMO) technology and so on. In some other documents, Filtered OFDM (F-OFDM) technology and universal filtered multicarrier (UFMC) technology are mentioned. Although these technologies are compatible with the CP-OFDM technology of the LTE, the out-of-band leakage is not inhibited well, and subcarriers in the bandwidth need to be synchronized strictly. That is, these technologies are still sensitive to frequency offset and time offset in sub-bands, with the demodulation performance of a receiving end decreased.
At present, in the premise of ensuring to be compatible with the LTE system as much as possible, it is unable to effectively inhibit out-of-band leakage and the demodulation performance of the receiving end is decreased.